Florfenicol is a structural analog of thiamphenicol, which in turn is a derivative of chloramphenicol [see, e.g., U.S. Pat. Nos. 4,235,892, 5,352,832, the contents of which are hereby incorporated by reference in their entireties].

Florfenicol is a broad spectrum antibiotic with activity against many gram-negative and gram-positive bacteria, including utility in the prevention and treatment of bacterial infections due to susceptible pathogens in birds, reptiles, fish, shellfish and mammals. One of florfenicol's primary uses is in the treatment of pneumonia and associated respiratory infections in cattle (often referred to generically as Bovine Respiratory Disease or BRD) caused by Mannhemia haemolytica, Pasturella multocida and/or Haemophilus somnus, also known as Histophilus somni. It is also indicated in the treatment of: pododermatitis in cattle caused by Fusobacterium necrophorum and Bacterioides melaninogenicus; swine respiratory disease caused by Pasturella multocida, Actinobacillus pleuropneumoniae, Streptococcus suis, Salmonella cholerasuis and/or Mycoplasma spp.; colibacillosis in chickens caused by Escherichia coli; enteric septicemia in catfish caused by Edwardsiella ictaluri; and furunculosis in salmon caused by Aeromonas salmonicida. Other genera of bacteria that have exhibited susceptibility to florfenicol include Enterobacter, Klebsiella, Staphylococcus, Enterococcus, Bordetella, Proteus and Shigella. In particular, chloramphenicol-resistant strains of organisms, such as K. pneumoniae, E. cloacae, S. typhus and E. coli, are susceptible to florfenicol.
Florfenicol is most often administered to subjects which can benefit from its advantages either orally or parenterally, the latter being primarily intramuscular or intravenous. Due to its very low water solubility (approximately one mg/mL), organic solvents must be added to achieve the desired product concentration in a commercial formulation. For example, in NUFLOR® (veterinary-labeled florfenicol formulation in the United States and Canada), the organic solvents N-methylpyrrolidinone, propylene glycol and/or polyethylene glycol are used to afford florfenicol solubility of 300 mg/mL. Unfortunately, when administered parenterally, these solvents often cause significant localized irritation. Therefore, there is a need for a more water-soluble form of florfenicol.
The citation of any reference herein should not be construed as an admission that such reference is available as “Prior Art” to the instant application.